PREMISES AND EQUIPMENT- Additional information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Impaired Long Lived Assets Held And Used [Line Items]
Depreciation and amortization expense	$ 20,100	$ 17,600	$ 15,000
Insurance proceeds related to casualty losses	0	587	7,673
Gain from insurance proceeds	5,000	660	537
Hurricane [Member]
Impaired Long Lived Assets Held And Used [Line Items]
Gain from insurance proceeds	5,000	100	500
Insurance Recoveries	$ 1,200
Hurricane [Member] | Property Plant And Equipment [Member]
Impaired Long Lived Assets Held And Used [Line Items]
Insurance proceeds related to casualty losses		$ 600	$ 2,000